This invention relates to postal matter or mail sorting apparatus for automatically sorting posta1 matter such as letter mail in accordance with the result of reading recognition of ZIP codes provided on the surfaces of the postal matter.
Various types of automatic postal matter processors have been proposed in order to save labor involved in work related to mailing service. One known type of automatic sorting apparatus described, for example, in British Patent No. 1527377, includes a code reader for automatically reading the ZIP codes on the postal matter and a plurality of stacking bins arranged in rows for stacking the postal matter in accordance with the readout ZIP codes. (For convenience the terms "postal matter" and "mail" will be used interchangeably to include broadly card, letter and periodical mail). However, with such conventional automatic sorting apparatus, the mail stacked at the bins is taken out of the bins manually by operators. The mail from each bin is then bound together with an address card identifying the proper ZIP code.
Therefore, the operators must manually withdraw the postal matter from the sorting apparatus which requires much walking and exertion to keep up with the sorting operation. Moreover, the efficiency of handling the mail is not good.
In view of the above, a sorting apparatus having an automatic push-out mechanism for pushing out the postal matter stacked in the stacking bins has recently been developed. In this kind of sorting apparatus, every time that a predetermined quantity of postal matter is stacked in a bin it is automatically pushed out from the stacking bin to the rear side thereof by the push-out mechanism. At the rear side of the stacking bins, a conveyance path is arranged parallel and adjacent to the row of stacking bins. The conveyance path conveys the postal matter taken out from the stacking bins in one direction to the binder unit.
When a particular sorting operation has come to an end, it is desirable that the postal matter stacked in each stacking bin is removed as a stack even if the predetermined amount of matter for a bin has not yet been reached. However, if any postal matter taken from a preceding bin is located on the conveyance path opposite a bin with letters in it, it is impossible to remove those letters at that time. Under these circumstances, the sorting apparatus controls the push-out mechanisms of the stacking bins such that the postal matter is pushed out of each stacking bin only after such postal matter as may previously have been on the conveyance path has moved to the end of the path. Alternatively, the postal matter can be taken out of all stacking bins except those bins blocked by postal matter on the conveyance path, and after that, the postal matter in the remaining stacking bins is taken out when the region on the conveyance path opposite to the remaining stacking bins is clear.
However, this is inconvenient in that it takes much time to take out all the postal matter from the stacking bins and the prior art apparatus does not work effectively.